The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
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Best Weight Loss Supplements For Men
When it comes to weight loss supplements for men, there's often confusion between over-the-counter options and prescription medications. In the UK, the most effective weight management tools are actually prescription-only medicines, not traditional supplements. If you have a BMI of 30 or above, or 27 with weight-related health conditions, you may be eligible for prescription weight loss medication through your GP or specialist services. This guide covers what works, what the evidence shows, and how to access proper weight management support in the UK.
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Calculate Your BMI Instantly
Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
Prescription Weight Loss Medications vs Traditional Supplements
The NHS acknowledges that prescription weight loss injections are far more effective than traditional supplements for significant, sustained weight loss. The two main prescription options licensed in the UK are Mounjaro (tirzepatide) and Wegovy (semaglutide).
Wegovy is a once-weekly GLP-1 injection that works by reducing appetite and helping you feel fuller after smaller meals. Clinical trials showed that men using Wegovy lost an average of approximately 15% of their body weight over 68 weeks, alongside a reduced-calorie diet and increased physical activity. Mounjaro is a newer dual GIP and GLP-1 injection that may offer slightly greater average weight loss—around 15–21% of body weight—though individual results vary significantly.
Traditional supplements like protein powders, fibre products, or caffeine-based fat burners have limited evidence for substantial weight loss on their own. Most work best when combined with calorie deficit and exercise, which is true of prescription medications too.
Try our free GLP-1 weight loss calculator to see what potential results might look like at different prescription doses, and use our BMI calculator to check your current eligibility for prescription options.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
How to Access Weight Loss Medication in the UK
Access to prescription weight loss medication in the UK works through two main routes: NHS specialist services or private online prescribing.
NHS route: Your GP can refer you to a tier 3 specialist weight management service. NHS availability varies significantly by region, and waiting lists can be long. Once assessed, a specialist may prescribe Mounjaro or Wegovy.
Private route: You can access prescription weight loss through a GPhC-registered online pharmacy following a clinical assessment with a UK-licensed prescriber. This doesn't require NHS referral and is often faster, though there is a cost (typically £129–£320 per month depending on dose).
Whichever route you choose, prescription medications work best alongside lifestyle changes: a reduced-calorie diet, regular physical activity, and behaviour change support. Use our free progress tracker to monitor your weight loss journey once you've started treatment.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
Are there over-the-counter weight loss supplements that actually work?
Some supplements like caffeine and glucomannan (soluble fibre) have modest evidence for supporting weight loss, but the effect is small compared to prescription medications or lifestyle changes. Most work best as part of a overall calorie deficit. Always check ingredients and speak to your GP before starting any supplement, especially if you take other medications.
Who is eligible for prescription weight loss medication in the UK?
Adults with a BMI of 30 or above, or 27 or above with at least one weight-related health condition (like type 2 diabetes, high blood pressure, or sleep apnoea), may be eligible. Eligibility is assessed individually by a prescriber. South Asian, Chinese, Black African, and Black Caribbean adults may qualify at lower BMI thresholds due to higher cardiovascular risk.
What's the difference between Mounjaro and Wegovy for men?
Both are prescription-only once-weekly injections. Wegovy (semaglutide) is a GLP-1 agonist with average weight loss around 15%. Mounjaro (tirzepatide) is a dual GIP and GLP-1 agonist with average weight loss around 15–21%. Mounjaro may be more effective for some men, but individual responses vary. Your prescriber will help determine which is appropriate for you.
How quickly will I lose weight on prescription weight loss medication?
Weight loss is gradual and sustainable. Most men lose 0.5–1 kg per week on average, though this varies based on dose, diet, exercise, and individual metabolism. Clinical trials show significant results after 16–20 weeks, with continued loss up to 68 weeks or longer. Results are best when medication is combined with a reduced-calorie diet and regular physical activity.
Can I get prescription weight loss medication through the NHS?
Yes. Your GP can refer you to a specialist tier 3 weight management service, where prescription weight loss medication may be considered if you meet the criteria. NHS access varies by region and waiting times can be lengthy. Private online prescribing is an alternative if you prefer faster access and are willing to pay privately.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.